1) A rent by the hour hot tub. Often found at sleazy places such as "Oasis" and other rent a tub facilities often accompanied by tanning beds (aka fake n bakers).

2) A place for your ex to take your best friend for a cheap make-out session.
Also, he will call you a week later, tell you about the hook up, claim it was in the name of "light conversation" and then tell you how sexually attracted to YOU he is (not your best friends he was just hookin' up with in a sleazy rent-a-tub).

3) A place where sleazy men take cheap woman.

Joe took Beth to a sleazy Rent-A-Tub (after inviting me there twice, i declined of course due to my sense of propriety), she shaved her legs for the event (after two months!), and after being denied by me (again) four days earlier Joe proceeded to come onto her- she happily obliged given that she has always coveted my life, my style, and apparently what was once mine.